Acrylate rubbers exhibit very favorable qualities of weatherability, high temperature serviceability, and good oil resistance. These qualities make the rubbers useful for under-the-hood automotive applications and out-of-door applications. Their use is limited by the tendency of the vulcanizates to post-cure during use. This results in property change and in some cases in failure of the article. To overcome these problems, the acrylate rubber vulcanizates are purposely post-cured, often as long as 24 hours or more, to obtain a more complete cure. This is shown by a reduced compression set. It would be of great advantage to the industry to reduce the time required for, or eliminate the need of, post-cure for the acrylate rubber vulcanizates.
Much effort has gone into the development of both faster and more efficient cures of acrylate rubbers. An article in Rubber Chemistry and Technology, Vol. 44, No. 2 (1971), traces the more recent efforts. Various cure sites and cure systems have been evaluated; see U.S. Pat. Nos. 3,288,763; 3,324,088; 3,337,492; 3,435,010; 3,450,681 and 3,458,461. However, the need for a long post-cure has not been eliminated, and improved vulcanizates are desired.